Question

Side of an equilateral triangle is measured as $3.6\pm .06$ cm, find percentage error in area of triangle

• A. 4.2 %
• B. 2.8 %
• C. 3.4 %
• D. 1.7 %

Answer 1

The correct option is C 3.4 %

% error of side (a) = $\frac{△a}{a}\times 100$
$=\frac{.06}{3.6}\times 100=\frac{6}{3.6}=\frac{60}{36}=\frac{10}{6}\simeq 1.7$
And, $A=\frac{\sqrt{3}}{4}{a}^2$
$\frac{dA}{A}\times 100=2\frac{da}{a}\times 100=2\times 1.7=3.4\%$